1

Inhibition of PDCD6 Induces Cell Proliferation and Reduces Apoptosis in Human Epithelial Ovarian Cancer Cells

Yan Huang, Xiaohua Wu

Department of Gynecology, Cancer Center, Fudan University

Yan Huang （ 310108197903152242）

Correspondence: Xiaohua Wu

Ovarian epithelial cancer is the leading killer among all gynecological malignancies.

Recent findings suggested that apoptosis and apoptosis-linked genes may play an important role in the development and progression of ovarian cancer (la Cour JM, et al. Mol Oncol. 2008).

Programmed cell death gene 6 (PDCD6), also known as apoptosis-linked gene-2 (ALG-2), is a 22 kDa penta-EF-hand type Ca2+-binding protein that was first reported by Vito in 1996. It is well recognized as an apoptotic mediator because PDCD6 expression is required for apoptosis following numerous death stimuli (Vito P, et al. Science. 1996).

Backgrounds

MethodsPoliferation

BrdU

Flow cytometry

RT-PCR, Western blot

Design of siRNA and construction of recombi-nant plasmids

Flow cytometry

Poliferation

Apoptosis

PDCD6

RT-PCR, Western blot

RT-PCR, Western blot

RT-PCR, Western blot

BrdU, Flow cytometry

Effects of cisplatin on ovarian cancer cells SKOV-3 and OVCAR-3

Transfection

SKOV-3 and OVCAR-3

Cell cycle

Apoptosis

Results RNAi inhibited PDCD6 expression in ovarian

cancer cells

Inhibition of PDCD6 prohibited apoptosis and increased cell proliferation

Inhibition of PDCD6 induced cell cycle

Cell cycle phase

Transfection group G0/G1(%) S(%) G2/M(%)

SKOV-3 control 75.23±1.17 16.87±0.58 7.90±1.39

SKOV-3 pRT-neg 76.73±1.53 15.40±1.21 7.87±1.45

SKOV-3 pRT-pdcd 56.77±1.48a 26.27±1.11a 16.97±2.56a

OVCAR-3 control 79.90±1.35 17.17±1.11 2.93±1.08

OVCAR-3 pRT-neg 78.27±1.00 17.30±1.13 4.43±2.05

OVCAR-3 pRT-pdcd 59.27±0.90b 22.17±1.80b 18.57±1.53b

• Cisplatin inhibited proliferation and increased apoptosis

• PDCD6 RNAi partly blocked the apoptotic effect and the anti-proliferative effect induced by cisplatin

Conclusions• 1. Inhibition of PDCD6 by RNAi induced cell

proliferation and cell cycle in SKOV-3 and OVCAR-3 cells by up-regulating cyclin D1, cyclin B1, cyclin E, and proliferating cell nuclear antigen (PCNA).

• 2. Inhibition of PDCD6 by RNAi reduced apoptosis in SKOV-3 and OVCAR-3 cells by decreasing cleaved caspase-3, cleaved caspase-7, cleaved caspase-8, Bax, death receptor 5 (DR5 ） and death receptor 4(DR4) and increasing Bcl-2.

• 3. Cisplatin increased cell apoptosis and prohibited cell proliferation while the mRNA and protein expression of PDCD6 was up-regulated.

• 4. PDCD6 RNAi partly blocked the apoptotic effect and the anti-proliferative effect induced by cisplatin. Cisplatin may inhibit proliferation and increase apoptosis partly through PDCD6.

• 5. PDCD6 plays an important role in the promotion and progression of ovarian cancer. PDCD6 is a candidate as a new target for ovarian cancer treatment.